package total;

import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

/**
 * 一场考试结束后，经常要统计一个班级的平均分。
	请写一个程序，计算每个班级的平均分。
 * @author chenxiaokang
 *
 */
public class Ques1007 {
	
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		List<Double> totalNumList = new ArrayList<Double>();
		List<Integer> totalScoreList = new ArrayList<Integer>();
		int score = 0;
		double totalNum = 0;
		double result;
		while(scan.hasNext()){
			totalNum = (double)scan.nextInt();
			score = 0;
			if(totalNum == 0){
				for(int i = 0; i < totalNumList.size();i++){
					result = (double)totalScoreList.get(i) / totalNumList.get(i);
					DecimalFormat df = new DecimalFormat("0.00");
					System.out.println(df.format(result));
				}
			}
			totalNumList.add(totalNum);
			for(int i = 0;i < totalNum; i++){
				score += scan.nextInt();
			}
			totalScoreList.add(score);
		}
	}
}
